Battery pack

A battery pack comprising:

• plural chargeable-dischargeable single cells arranged in a specified direction, wherein each of the plural single cells includes:
• an electrode body including a positive electrode and a negative electrode;
• and
• a box-shaped battery case accommodating the electrode body and an electrolyte,
• wherein the battery case has a flat surface that is a surface perpendicular to a thickness direction of the battery case, and a lateral wall surface that is a surface parallel to the thickness direction and wherein the lateral wall surface extends from the flat surface,
• wherein the battery case has a gas discharge valve formed in the flat surface,
• two adjacent single cells of the plural single cells in the battery pack are provided with gas discharge valves in mutually opposing surfaces of the battery cases, each of the gas discharge valves discharging gas that is produced in the battery case, and
• in the battery cases provided in the two adjacent single cells, the gas discharge valves that are provided in the mutually opposing surfaces are disposed at positions that do not overlap each other when seen in an arrangement direction of the single cells.